摘要
      整合素是一种遗传元件，可以通过插入和移除基因来促进抗生素耐药性的快速传播。然而，关于嵌入1类整合素的基因盒的多样性和分布的知识仍然有限。在这项研究中，我们使用纳米孔测序对整合子基因盒进行了测序，并量化了生物反应器施肥土壤和污水中的抗生素抗性基因（ARGs）和整合酶基因。结果表明，与2类和3类整合酶基因相比，1类整合子整合酶基因在土壤和污水中最丰富。长期施用粪肥加剧了总ARGs、整合酶基因和抗生素耐药性相关基因盒的富集，而抗生素和重金属对总体耐药性没有影响。污水处理可以有效去除整合酶基因的绝对丰度（约3个数量级，拷贝数/L）和抗生素抗性基因盒。抗性基因盒主要携带对土壤和污水中氨基糖苷类和β-内酰胺类产生抗性的ARGs，其中一些在污水处理过程中是持久的。这项研究强调，土壤和污水是整合子介导的ARGs转移的潜在库，表明人为活动在整合子中抗性基因盒的流行和多样性中发挥着至关重要的作用。
Abstract
Integrons are genetic elements that can facilitate rapid spread of antibiotic resistance by insertion and removal of genes. However, knowledge about the diversity and distribution of gene cassettes embedded in class 1 integron is still limited. In this study, we sequenced integron gene cassettes using nanopore sequencing and quantified antibiotic resistance genes (ARGs) and integrase genes in the manured soils and sewages of a bioreactor. The results showed that class 1 integron integrase genes were the most abundant in soils and sewages compared with class 2 and class 3 integrase genes. Long-term manure application exacerbated the enrichment of total ARGs, integrase genes and antibiotic resistance-associated gene cassettes, while antibiotics and heavy metals showed no impact on the overall resistome profile. Sewage treatment could efficiently remove the absolute abundance of integrase genes (~3 orders of magnitude, copies/L) and antibiotic resistance gene cassettes. The resistance gene cassettes mainly carried the ARGs conferring resistance to aminoglycoside and beta-lactams in soils and sewages, some of which were persistent during the sewage treatment. This study underlined that soil and sewage were potential reservoirs for integron-mediated ARGs transfer, indicating that anthropogenic activity played a vital role in the prevalence and diversity of resistance gene cassettes in integrons.

https://www.sciencedirect.com/science/article/abs/pii/S0048969721078451